package leetcode7;

public class test25 {
//    21. 合并两个有序链表
    //双指针
    class Solution {
        public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
            ListNode dum = new ListNode(0),cur = dum;
            while(list1 != null && list2 != null){
                if(list1.val >= list2.val){
                    cur.next = list2;
                    list2 = list2.next;
                    cur = cur.next;
                }else if(list1.val < list2.val){
                    cur.next = list1;
                    list1 = list1.next;
                    cur = cur.next;
                }
            }
            cur.next = list1 == null ? list2:list1;
            return dum.next;
        }
    }
}
